a) Field of the Invention
The present invention relates to a peelable sealing sheet for use to close in a reversible manner a plurality of individual pill containers.
The invention also relates to a method for manufacturing this peelable sealing sheet.
The invention further relates to a set of individual pill containers comprising a sheet of plastic material defining a plurality of individual containers closed in a reversible manner by the so-manufactured peelable sealing sheet.
b) Brief Description of the Prior Art
It is of common practice in the pharmaceutical field to prepare sets of individual containers containing pills and/or tablets to be administered to a patient. Each of these containers contains pills and/or tablets that the patient has to take together at the same time during the day over a given period of time (preferably one week).
To prepare such sets of individual pill containers for use by a patient, it is also of common practice to use a sheet of plastic material in which a plurality of recesses are molded. Each of these recesses defines a small upwardly opened container that can be filled with pills. After filling, all the containers are closed by means of a sealing sheet on which all desirable indications can be printed, like the patient""s name, the date and hour of administration, etc. As it can be understood, the indications are printed and formatted onto the sealing sheet so that each group of information referring to a given container is positioned in regard to said container. Tearing lines are provided on both the container-defining sheet and the sealing sheet to permit easy separation of the individual pill containers.
In practice, the sealing sheet can be made of plastic material and be thermosealed onto the container-defining sheet. Alternatively, the sealing sheet can be made of paper and be glued onto the container-defining sheet.
For further information as to the structure, manufacture and use of such sets of individual pill containers, reference can be made to U.S. Pat. No. 5,788,079 and its Canadian counterpart No. 2,207,045 both in the name of the present inventor, and to all the prior art that was cited during their prosecution.
If, so far, the existing sets of individual pill containers have proved to be particularly useful and efficient, they still suffer from a major deficiency, viz. the fact that once a given container of the set is opened by tearing or peeling off the corresponding portion of the sealing sheet, it cannot be closed again. Thus, if there has been any mistake in the way one or more of the containers were originally filled with pills, there is no way of repairing this error and one must get rid of the whole set. Similarly, if the patient or his/her nurse has not opened the right container by inadvertence, there is no way of repairing this error since the inadvertently opened container cannot be closed back.
In Canadian laid-open patent application No. 2,264,339 also in the name of the present inventor, there is disclosed a reversible peelable sealing sheet made of paper, which, thanks to its structure, solves all the problems related to the above mentioned deficiency inasmuch as it allows each of the containers of the set to be opened and closed back whenever desired, even when the container is still part of the set. This sealing sheet comprises three layers, namely:
a top layer made of paper;
an adhesive layer made of a sheet of paper whose upper and lower surfaces are covered with a layer of pressure sensitive adhesive glue; and
a peelable backing.
The adhesive layer has precut central pieces surrounded by bands. Similarly, the backing has precut central pieces surrounded bands that are positioned shaped and sized to be in exact superposition below the central pieces and surrounding bands of the adhesive layer.
The precut bands of the backing define a protective peelable covering that is peeled off before installation of the sealing sheet on top of the container-defining sheet. The central pieces of the adhesive layer and of the backing remain sticked to each other and to the lower surface of the top layer and altogether form a plurality of non-sticking protective pads fitting on top of the cavities made in the container-defining sheet.
This sealing sheet is quite efficient. However, it has been found that, in use, some of the central pieces unstick from the top layer and fall down when the sealing sheet is installed or when, after installation, one tries to open some containers. Then, when the containers are closed back, the pills stored therein may stick to the bottom surface of the top layer on which some adhesive always remains.
A first object of the present invention is to provide a reversibly peelable sealing sheet for use to close a container-defining sheet, which is as efficient as the one disclosed in Canadian laid-open application No. 2,264,339 but does not have the same drawback in use.
The sealing sheet according to the invention basically comprises:
a top layer made of paper and having an upper surface defining the top surface of the sealing sheet, and a lower surface; and
an adhesive layer made of paper and having a plurality of spaced apart holes punched therein, the holes being surrounded by adhesive layer bands that form said adhesive layer, the adhesive layer bands having an upper surface covered with an upper layer of pressure sensitive adhesive glue and a lower surface covered with a lower layer of removable re-positionable pressure sensitive adhesive glue, said adhesive layer bands being fixed to the lower surface of the top layer by the upper layer of pressure sensitive adhesive glue;
a peelable backing having a plurality of spaced apart holes that are positioned, shaped and sized to be in exact superimposition below the holes of the adhesive layer, the holes of the backing being surrounded by backing bands that forms said backing, the backing bands having an upper surface detachably fixed to the lower surface of the adhesive layer bands by means of the lower layer of removable re-positionable pressure sensitive adhesive glue, whereby the backing bands can be peeled off from the adhesive layer bands to allow fixation of the sealing sheet onto the container-defining sheet; and
tearing lines punched into the top layer and the adhesive layer bands in such a manner and position as to allow the top layer and adhesive layer to be split into a number of cover pieces equal to the number of holes made in the adhesive layer, each of the cover pieces having one of the holes of the adhesive layer that is centrally positioned therein and fully surrounded by a flange made of parts of the adhesive layer bands.
As can be appreciated, there are no more central pieces left onto the adhesive layer and the peelable backing. Rather, these pieces are removed thereby leaving holes below the top layer, which are sized, shaped and positioned to extend over the containers of the container-defining sheet.
A second object of the invention is to provide a method for manufacturing peelable sealing sheets according to the invention as defined hereinabove. This method comprises the steps of:
a) providing a three-layered sheet comprising:
a central sheet made of paper and having an upper surface covered with an upper layer of pressure sensitive adhesive glue and a lower surface covered with a lower layer of removable re-positionable pressure sensitive adhesive glue;
an upper backing sheet fixed to the upper surface of the central sheet; and
a lower backing sheet detachably fixed to the bottom surface of the central sheet;
b) punching the three-layered sheet in order to cut spaced apart sets of superimposed pieces into both of the central sheet and the lower backing sheet;
c) peeling off the upper backing sheet together with the sets of pieces cut into the central sheet and lower backing sheet of the three-layered sheet, whereby a two layered sheet made of the central sheet and lower backing sheet with holes therein corresponding to the peeled off pieces is obtained, the holes being surrounded by bands left into the central sheet and the lower backing sheet,
d) providing a single sheet of paper;
e) applying the single sheet of paper onto the upper surface of the central sheet of the two-layered sheet obtained in step c) so to form another three-layered sheet;
f) punching tearing lines into the single sheet of paper and the bands of the central sheet of the three-layered sheet obtained in step e) in such a manner as to allow the single sheet of paper and the bands of the central sheet to be slit whenever desired into a number of cover pieces equal to the number of holes made in said central sheet; and
g) punching cutting lines in the punched, three-layered sheet obtained in step f) to facilitate splitting of this three-layered sheet into the requested sealing sheets, the so cut-single sheet, central sheet and lower back sheet respectively acting as top layer, adhesive layer and backing of each of the so obtained sealing sheets.
A third object of the invention is to provide a set of individual pill containers comprising a sheet of plastic material defining a plurality of individual containers closed in a reversible manner by the so-manufactured peelable sealing sheet.
The invention and its advantages will be better understood upon reading the following non-restrict description of a preferred embodiment of the invention, made with reference to the accompanying drawings.